Yes. When you copy the database, you might have more data on the slaves then the normal replication system would copy, but this does not hurt. If you want to remove some data on the slaves, then you can safely delete all data were the server_id of the record does not match the server_id of the server or server_id != 0 as records with server_id = 0 have to be replicatde to all servers. If a database table has no serevr_id column, then its saver to not delete any data in that table.